meconium

American  

[mi-koh-nee-uhm] / mɪˈkoʊ ni əm /

noun

1. the first fecal excretion of a newborn child, composed chiefly of bile, mucus, and epithelial cells.

2. fecal mass released at pupation by the larvae of some insects.

3. the milky sap of the unripe seed pods of the opium poppy; crude opium.

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meconium British  

/ mɪˈkəʊnɪəm /

noun

1. the dark green mucoid material that forms the first faeces of a newborn infant

2. opium or the juice from the opium poppy

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Etymology

Origin of meconium

1595–1605; < Latin < Greek mēkṓnion, diminutive of mḗkōn poppy

Example Sentences

They’ve also been detected in blood, breast milk and even meconium — an infant’s first stool.

From Los Angeles Times • Apr. 2, 2026

In February 2023, when she was almost 42 weeks pregnant, Sophie discharged a dark substance which she thought was meconium, a baby's first stool.

From BBC • Feb. 12, 2026

The group is now investigating the occurrence of microbial metabolites in other mammals: piglets and calves, as well as in the meconium and amniotic fluid samples of babies.

From Science Daily • Nov. 1, 2023

Lo wrote that doctors discovered her newborn swallowed meconium, which led to pneumonia.

From Los Angeles Times • Oct. 11, 2023

At birth the bowels of the calf contain the meconium, a tenacious, gluey, brownish-yellow material largely derived from the liver, which must be expelled before they can start their functions normally.

From Special Report on Diseases of Cattle by United States. Bureau of Animal Industry